Method for producing a dental model and carrying plate for receiving same

ABSTRACT

The invention relates to a method for producing a dental model for removable insertion in a recess of a holder, which dental model has a referencing, comprising at least one tooth part having a base to be inserted into the recess, wherein the at least one tooth part is produced using digitized data of a jaw in that the digitized data are saved in a computer beforehand and supplied to a processing machine to produce the at least one tooth part. In order to ensure simple handling of the dental model and in particular to prevent faulty insertion of the dental model or segment, according to the invention the referencing is saved in the computer and, in consideration of the referencing, the at least one tooth part is produced as having the base as a unit.

The invention relates to a method for producing a dental model for removable insertion in a cut-out or recess of a holder, cut-out or recess which has a referencing, dental model which includes at least one tooth part with a base, which or a section thereof is inserted in the recess, wherein, using digitized data of a jaw or of a section thereof, the at least one tooth part is produced, in that the digitized data are saved beforehand in a computer, and with the use thereof are supplied to a processing machine to produce the at least the one tooth part, wherein the referencing of the recess is saved in the computer, and in that at least one tooth part with the base is produced as a unit taking into consideration the referencing, and wherein, as holder, a plate-shaped element with upper face and lower face as well as the recess having a curved shape is used, recess which is delimited by lateral surfaces, which is provided with the referencing.

The invention further relates to a carrying plate for receiving a denture model or a segment or several segments of such a denture model, wherein the denture model or the at least one segment comprises a base with a tooth part or several tooth parts, and wherein the carrying plate has an upper face and a lower face and a cut-out with side surfaces extending along an arc, in the manner of a denture arch, side surfaces of which at least one, preferably both, has/have a referencing which forms a first guide for the base.

Another subject matter of the invention is a dental device comprising a dental model, consisting preferably of at least two segments, as well as a carrying plate for receiving the dental model in a removable manner in a cut-out, wherein the dental model comprises at least one tooth part, preferably at least two tooth parts, which originate(s) from a base.

In order to produce a dental prosthesis, according to a commonly used technique, a dental imprint is first made of a denture or of a portion of such a denture after a preparation has been performed beforehand by a dentist, imprint which reproduces the negative situation in the mouth of a patient. From the resulting formed negative model, a positive model is produced, which includes the area of the jaw that is to be provided with the dental prosthesis. In the case of one or more tooth stumps, the jaw area is also molded.

In order to produce a dental prosthesis on the basis of a corresponding master model, it is possible to carry out an exclusively manual manufacturing or a manufacturing in which the area in question is scanned and the resulting digitized data are used for producing dental prosthesis by the CAD/CAM method. Here it is necessary that either beforehand the model to be referred to as duplicate is severed into duplicate sections, which are then scanned individually. In order to be able to assign the duplicate sections to one another, it is necessary moreover for a correlation with the entire duplicate to be carried out. Thus, the duplicate itself and also the duplicate sections has/have to be scanned (EP-B-0 913 130).

In order to avoid these disadvantages, it is known from EP-B-1 691 712 to scan the duplicate without severing it, wherein the individual scans are assigned to one another on the basis of a referencing present on the duplicate.

A dental model can be obtained from WO-A-2010/099959, which consists of a base part with recesses and of tooth parts to be inserted therein. In order to prevent faulty insertion of tooth parts into the base part, the tooth parts comprise orienting projections.

In order to produce a master model, according to WO-A-98/10709, a carrying plate with recesses is used, carrying plate which is delimited by side surfaces having a structuring. In the bottom area of the carrying plate, bore holes are present into which the pins of segments of the model can be inserted, in order to ensure a proper positioning of the segments.

A corresponding technique can also be obtained from WO-A-01/06945. This document describes a carrying plate with tooth crowns produced by rapid prototyping. For the fastening of the tooth crowns, the carrying plate has a continuous cut-out delimited by guide grooves, in order to be able to pour foundation material through the cut-out for the fastening of the lower face of the tooth crown.

From WO-A-2007/117239, a method can be obtained for automatically producing a mold for a dental prosthesis. For this purpose, the jaw area in question is scanned intra-orally. In the process, a tooth base is formed, which has an opening for receiving a prefabricated abutment.

In WO-A-2011/103879, a computer-implemented method for generating a virtual model of a set of teeth is described, in order to produce a physical model on the basis thereof.

A carrying plate for a model is described in U.S. Pat. No. 5,506,095. The carrying plate has a cut-out with inner faces, which extends along a jaw arch, inner faces which are used as referencing, in order to allow a reinsertion of a cured mold in the cut-out. The bottom has a slit, into which an element, in particular an element made of plastic, can be inserted in order to form an intermediate layer with respect to the model and to allow easy insertion and removal from the carrying plate.

The subject matter of DE-B-10 2004 054 876 is a measuring device for 3D measurement of dental models. For this purpose, a dental model is recorded in different known rest positions. This facilitates a matching of the individual recordings.

A mold for producing a dental model is known from DE-C-197 22 989. It comprises a model plate as well as an impression tray which carries a dental imprint. The hollow space between the imprint mold and the model plate is filled with a molding material. From said molding material, sections of pins originate, which can be inserted in corresponding openings of the model plate.

In EP-A-1 520 551, a work table for dental technicians and dentists is described, which is used to produce an implant bore template.

A method for generating a computer model of a denture on the basis of digital information is the subject matter of US-A-2008/0085489.

A guide template for producing dental prostheses is described in WO-A-2008/117323.

WO-A-2002/39056 relates to a surface acquisition and generation device.

In order to produce a dental prosthesis using the CAD/CAM technology, DE-A-10 2005 009 549 provides for fastening a dental model produced by a conventional method, in a base plate, using gypsum or adhesive, for example. In order subsequently to scan segments cut from the model and to match the scan data, the base plate has a referencing formed by wave geometry.

From the prior art, a method can be obtained in which a jaw area is scanned intra-orally, and on the basis of these data a dental model is produced, wherein segments of said model are fastened by means of pins in a drilled board. In order to rule out transposition of the segments, a setup plan is added to the drilled board on which the segments are to be arranged. This leads to a complicated operability and in the end it does not ensure an incorrect occupation of the drilled board.

US-A-2010/0152873 describes a method for producing a dental model. Here, first a jaw is scanned, making it possible then to produce, for example, by rapid prototyping, a tooth part, which has a base consisting of one or several references.

FR-A-2 715 826 describes a carrier for a dental model. The carrier has passage openings which are bridged on the bottom face by ribs.

The aim of the present invention is to further develop a method, a carrying plate as well as a dental device of the type mentioned in the introduction, in such a manner that a simple operability of the dental model is ensured, in particular ruling out a faulty insertion of the dental model or of the segments into the holder or carrying plate. At the same time, the dental model should be such that it can be produced with high precision, using the desired materials.

According to an additional aspect, it is to be ensured that the segments are fastened in a manner so that they cannot fall out, independently of their width extension in the recess or cut-out of the holder or carrying plate, wherein even frequent removal and reinsertion should not lead to any deficiencies.

In accordance with the method, the aim is achieved essentially in that the recess on the underside is delimited by a bottom wall in which a longitudinal slit is present, and in that the base, on the bottom face, is formed with a first projection for the insertion in the longitudinal slit and/or in that the plate-shaped element, on the upper face, has a first section which is set back with respect to the surface and which extends along the recess and transitions into said recess, and in that the base is produced in such a manner that from it a laterally protruding second projection originates, which is adapted to the set back first section or to an area thereof.

The referencing consists in particular of a structure formed by projections or indentations at least in an area of the recesses in which the base is inserted, base which is produced with the at least one tooth part as a unit, in particular by the CAM (Computer Aided Manufacturing) method.

Deviating from the known prior art, the dental model is produced with a base which has a referencing that corresponds to the holder receiving the dental model. In this manner it is ensured that after the production of the dental model, a faulty insertion into the holder is ruled out, in particular in the case where only individual segments are produced, which are then to be inserted for the production of the dental prosthesis in the holder for modeling the framework or the veneering.

The base and the tooth part are produced as a unit made from the same material, such as, for example, plastic.

A dental model usually comprises a model of the upper jaw and the lower jaw.

Therefore, the invention provides in particular for the dental model to be produced in the form of at least two adjoining segments, wherein at least one segment, preferably each segment, comprises two tooth parts with common base.

As a result of the feature of the set back section of the plate-shaped element and of the adapted projection of the base plate, the base part is in contact over a relatively large surface area with the holder, and consequently it is not,—as is the case in the prior art—attached exclusively in the cut-out itself, but is applied instead additionally by means of the laterally protruding second projection, which rests on a delimitation of the first section, which extends parallel to the surface of the holder.

The dental model itself can be a master model or a work model. The work model differs from the master model in that, in the first model, the gingival tissue is removed at the stumps to which the dental prosthesis is to be applied. This is important in order to be able to determine the preparation boundary. The possibility exists of producing segments with a preparation boundary and segments with no preparation boundary that is with gingiva. In the case where there is no gingiva contour present, a segment with concave molding is obtained. Interposing identical segments, which thus have identical stumps, results in the advantage that either 

1. Method for producing a dental model (12) for removable insertion in a cut-out or recess (34) of a holder (10, 100, 200, 300), cut-out or recess which has a referencing, dental model which includes at least one tooth part (24, 26, 28, 66) with a base (30, 32, 68), which or a section thereof which is inserted in the recess, wherein, using digitized data of a jaw or of a section of said jaw, the at least one tooth part is produced, in that the previously digitized data are stored in a computer and with the use thereof are supplied to a processing machine for producing the at least one tooth part, characterized in that the referencing of the recess (34) is stored in the computer and in that at least one tooth part (66) with the base (30, 32, 68) is manufactured as a unit taking into consideration the referencing.
 2. Method according to claim 1, characterized in that the dental model is produced in the form of at least two mutually adjoining segments (14, 16, 18, 20, 22, 24), wherein at least one segment, preferably each segment, has at least two tooth parts with common base (30, 32, 68).
 3. Method according to claim 1 or 2, characterized in that, as holder (10, 100, 200, 300), a plate-shaped element having an upper and lower face (36, 38) as well as the recess (34) having a curved shape is used, which is delimited by side surfaces (52, 54), which is provided with the referencing.
 4. Method according to at least one of the previous claims, characterized in that the cut-out (34), on the underside, is delimited by a bottom wall with longitudinal slit (40) present in said bottom wall, longitudinal slit which optionally passes continuously through the bottom wall, wherein the base (30, 32, 68), on the underside, is formed with a first projection (64) for the insertion in the longitudinal slit.
 5. Method according to at least one of the previous claims, characterized in that the plate-shaped element, on the upper face, has a first section (82) which is set back relative to the surface and which extends along the recess (34) and transitions into said recess, and in that the base (64) is produced in such a manner that, from said base, a laterally protruding second projection (72) originates, which is adapted to the set back first section or to an area thereof.
 6. Method according to at least one of the previous claims, characterized in that, on the basis of the dental model, a dental prosthesis is manufactured manually and/or by CAD/CAM methods.
 7. Carrying plate (10, 100) for receiving a denture model (12) or a segment or several segments of such a denture model, wherein the denture model or the at least one segment has a base (68) with a tooth part (66) or several tooth parts, and wherein the carrying plate has an upper and a lower face (36, 38) and a recess or cut-out (34) extending along an arc, in the manner of a denture arch, with side surfaces (52, 54) which have or of which at least one has a referencing which forms a first guide for the base, wherein the base and the tooth part are manufactured as a unit from the same material, characterized in that the upper face (36) of the carrying plate (10, 100) has a set back area (82) extending along the cut-out (34), as second guide for the base (68), and/or the cut-out has, on the underside, a slit (40) extending along the cut-out, as third guide for the base.
 8. Carrying plate according to claim 7, characterized in that the slit (40) is formed as a cut-out with preferably a V- or U-shaped cross section in the bottom wall (35) or passing continuously through the bottom wall.
 9. Carrying plate according to claim 7 or 8, characterized in that the slit (40) is bridged on the underside by at least one rib (42, 44, 46, 48) which extends transversely to the longitudinal direction of the slit.
 10. Carrying plate according to at least one of claims 7 to 9, characterized in that the first guide is formed by the side surfaces (52, 54) each having a wave geometry, with bumps (56, 58, 60, 62) and indentations extending perpendicularly to the upper face (36).
 11. Carrying plate according to at least one of claims 7 to 10, characterized in that the distance between the bumps (56, 58) of one side surface (52) differs from the distance between the bumps (60, 62) of the other side surface (54), in particular the distance between two bumps of the side surface extending along the outer arch is 1.5 to 10 times, preferably 2 to 5 times greater than the distance between two bumps of the opposite side surface extending along inner arcs.
 12. Carrying plate according to at least one of claims 7 to 11, characterized in that the at least one rib (42, 44, 46, 48) is guide and/or fastening for an articulator.
 13. Dental device comprising a dental model (12), consisting preferably of at least two segments (14, 16, 18, 20, 22), as well as a carrying plate (10, 100) which receives the dental model in a removable manner in a recess or cut-out (34), wherein the dental model has at least one tooth part (66) originating from a base (68), preferably at least two tooth parts, and the tooth part and the base are manufactured as a unit from the same material, characterized in that the carrying plate (10, 100) has, on the upper face, an area (82) which is set back with respect to the surface of said carrying plate and which extends along the cut-out (34), and the base (68) comprises a section (72) which is adapted geometrically to the area, and/or the cut-out comprises a slit (40) which extends along the cut-out, and the base comprises a projection (64) which is adapted geometrically to the slit.
 14. Dental device according to claim 13, characterized in that the segments (14, 16, 18, 20, 22) are arranged one after the other in the cut-out (34), and in that preferably at least two tooth parts originate from a common base.
 15. Dental device according to claim 13, characterized in that the segments (14, 16, 18, 20, 22) inserted in the carrying plate (10, 100) have a gap A where A<0.1 mm, in particular A<<0.1 mm.
 16. Dental device according to claim 13, characterized in that the segments (14, 16, 18, 20, 22) are produced by the CAM method. 